


The Experiment

by rbssns



Series: Yandere One-shots [2]
Category: Undertale (Video Game)
Genre: F/M, Papyrus really cares, Sans and his fucken notes, Yandere Sans, Yandere Sans and reader, he's trying to help, reader is female, updating Tags a I go
Language: English
Status: In-Progress
Published: 2017-12-27
Updated: 2018-05-28
Packaged: 2019-05-14 17:43:50
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 3
Words: 3,196
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14774222
Author URL: https://archiveofourown.org/users/rbssns/pseuds/rbssns
Summary: This a random one-shot collection of Yandere Characters and the reader. I haven't gotten that to far into writing it, an yes there are grammar errors. So sorry in advance for those but i hope you enjoy it.





	1. Chapter 1

**Author's Note:**

> Sorry for the re-upload an everyone that Subscribed before. please do so here an thank you again for the understanding. This story was brought about from an rp party that happened from 
> 
> crappyartforyou.tumblr.com
> 
> Please do go and check them out they are fantastic.

You wake up in a dark room, not knowing where you are. As you listen, you hear a lots of sounds above you, making you think you’re in a basement. 

"Hello?" you call out, but no one seems to hear you.

The noise upstairs gets louder. It sounds like a party, withloud bumping music causing the chains to shake with every deep vibration. You stand up dusting yourself off. Looking around the basement as much as you could with the little to no light. It looked like this room is being used for storage. As you move around boxes, stepping over a large chains scattered on the ground. A rope catches your other foot causing you to trip into the cage . A light, metallic sound brings your attention to a small artificial light around a corner. You  make your way over, cautiously peeking inside to see if anyone is around.

 "H-Hello? is anyone there? Please, I don't know where I am. I just woke up here."

The sound of your voice catches Sans off guard. He turns to assess the source of the noise." That's strange. I don't remember inviting anyone here. I'm suppose I should introduce myself. Name’s Sans, and yours is...?"

Sans opens the door fully to see you,making sure to keep the bloody rag behind his back.  He sets his recently cleaned tools back in their designated spots.

  " Oh . . um . . .  I'm y/n. " You let out an excited gasp "Is that a cat’s claw?!?" As you focus on the tool, Sans slyly tosses the bloody rag into a bin. Enthralled, you reach for the cat’s claw, not even noticing you’re holding Sans’s hand as well. HE doesn't pull away from your touch. You notice you’re too close and quickly let go, taking a few steps back  holding your hands together close to your body. "S-Sorry about that."

"No you're fine. You like things like this?" He grins, eyelights wide.  _Interesting_.

 Sans question makes you look shyly away, " y-yeah, but its not really useful thing in life to know these sort of things. . . . . .  So . . . where is this place, and how did i get here?" Something about the way Sans looks at you makes you squirm. You try to look at the tools and avoid direct eye contact with him.

"Most likely an anomaly. Did you have anywhere to be?" _Anyone who’ll come looking for you when you’re gone?_  

You think for a moment as you look at the weapons on the wall." No, I was just walking home from work about to get myself some food,when I was invited to a party by this robot. When I passed through the front door of the club everything went black." you toy with a few of the weapons on the wall, a small smile still on your face."Why are you here? it sounds like things are happening up there"

Sans makes a mental note to clean the tool that you touched. "Yeah that's the party going on upstairs. Although I don't care for crowds all that much, so i'm staying in my lab.What about you? Are you much of a   _people_  person?"

You let out a small sigh and force yourself to make eye contact. " Not really. Not too many people I would actually talk to, let alone hang out with ." You place your hands inside you pocket looking at the ground.." so . . .  Which ways the exit? I've gotta get some food in me."

 Sans shrugs and goes back to wiping down the exam table, "I actually have some food down here I snuck from the party, if you don't wanna go upstairs. I mean I actually don't mind your company, so you can stay if you like."A light blush creeps into your cheeks as you watch him work " T-Thank you but I'd feel bad if I ate your food. To   _patella_  the truth, not many like talking to me, but I find myself quite   _humerus._ "

 Sans smiles at your attempt to joke. "No worries, I wasn't going to eat it all anyways.   _Tibia_  honest, I think you’re very sweet so I don't mind sharing." Sans complements turns you red as a tomato, and you try to hide your face in your hands. Not wanting to disturb the tools on the wall, you sit on the ground, taking a few deep breaths to calm your red face. Repeating over and over in your head   _"He didn't mean it. he didn't mean it. he didn't mean it."_  

Sans notices the long pause and turns  to see what went wrong. He is pleasantly surprised at the blush on your face and walks a bit closer. "You were sweet to me, so I'm assuming that you are to others. But there are some things I can see as a fact." He reaches down and brushes some stray hairs out of your face, smelling your hair without making a sound. " You're beautiful, and witty. I see that and I've only known you for about 10 minutes.  _More importantly, though, you’re weak-willed, shy, and easy to fluster. Absolutely perfect_.

"You stutter,failing to form a single word. As you look away from Sans, your blush comes back in full swing. "I-I guess, but usually others don't see it as that, and treat me badly." You let out a fake cough to try to slow down your pounding heart.. But it wasn't working. "  _Why am I telling him all these things?"_ You ask yourself,  tearing your eyes as far from Sans’s as possible. "I better go before I make a bigger fool of myself." 

Sans’s frozen smile goes just a bit wider. It’s so easy to affect you with just his words. He wonders how he could affect you with the fun things on his wall. Like that cat claw you were so interested in moments ago . "You sure you wouldn't want rather stay? Besides, I wouldn't say you look like a fool." you get up off the floor and search for a door in the minimal lighting. . Keeping your back facing Sans," So what do I look like to you if not a fool?"

_Prey. You look like prey. The best I’ve had in a long time_."Cute."

Upon seeing no way leading out, you turn back." I--I am far from that, but thanks . . . you mentioned food?" You look at him sheepishly, not knowing what to do next.

"That's your opinion, but my fact is that you are cute," Sans points over to the plate with pizza and cookies. "Help yourself." His eyelights trail down to your lips as you put the first bites of pizza in your mouth.

"If you don't mind me asking, what is this lab for? What are you studying?"

_Ah, you’re stalling for me. Just a little longer for me, pet_." Humans and monsters.It’s pretty fascinating, actually." He wonders when the sedative will kick in. 10 maybe 15 minutes at most.

" I can see that. There are differences between us, but we’re still similar- " You blink a few times and try to settle your head in your hands, but the room won’t stop spinning. ”Sans?” You reach towards his hand,  but you overreach and fall out of your chair with a heavy crash.  " That was fast."  Sans takes his time walking towards you, savoring the fear in your frozen body as well as checking for damage from the fall. He doesn’t see anything serious, which is nice. He wants you intact, just like that, so he can relish breaking you down piece by piece. He runs his hand across your face, and locks it onto your neck.

" What’s wrong, Y/N? Am I leaving you breathless already?" He laughs racously, and his skull catches the light in the worst way possible.

You thrash wildly, fighting your body’s atrophy, but you burn through your remaining oxygen quickly and go limp under his grip.  Sans uses his magic to open the cage door, then tosses you in and locks the door.

" _I'm guessing you'll be confused  when you wake up, Pet. That won't last long. I’ll show you the ropes real soon_. Sans chuckles into his hand, as the slammed door’s echo rings in the dark.


	2. Chapter 2

When you come to, you’re caged up, still in the basement.  You try to open the door to find it locked.

Your thoughts go back to what happened before you blacked out.

" Oh,h no." You scan the room quickly, looking for any signs of Sans.

"Sans, SANS!! Are you okay?!" No response.  _I hope you’re safe_ , you pray as you grip the bars tightly. At last, Sans comes into view.

"I'm here, but shouldn't you be more worried about yourself?" You sigh with relief as Sans moves around the cage.

" Well . . . . yeah, but this isn't the first time I've been locked in a cage.And I figure it won’t be the last. ” You try to keep the quiver out of your voice and press further.

“So tell me something. What kind of person are you? Are you a maniac looking to experiment on me? Kill me, torment me, sell me off?!" Your voice gets louder with each accusation.  ,"WHICH IS IT?"

It’s working. Sans fights to keep his face expressionless,  but it’s difficult to hold back the smile at the corner of his mouth. "I think you were closest with experiments."

"So that’s what you want. Just fucking great.”" You crawl away from Sans and sit  in the middle of the cage. Your spirits sink as you’re hit by the gravity of your situation.," Figures."

" Ya know, I was a little surprised that you fell into such an easy-avoided trap. Luckily, the sedatives don’t have any negative side effects."

" Yeah, yeah,  just rub it in. The one time I let my guard down..." Your voice lowers to a whisper. "The one time I thought I actually made a friend." You let your HP drop by 2 points.

Sans notices your HP drop.  _Remember, you need this one to last longer than the last one._. "If it makes you feel better, there wasn't any way that you were going to get out of here. You actually found the least painful way to get into that cage."

"It doesn't," You keep your back towards him, refusing to meet his gaze. Even if he stabs you in the back (twice), there’s not true way to avoid it.

",J-Just do what you want already and be done with it. This isn’t my first time in a cage. I know you’re just looking for results." Knowing what’s coming brings you little comfort, and you hug your knees to your chest as tightly as you can.

" Last one?" Sans’s steps pause at your words, as he waits for you to continue. " Yeah, the last freak that tried to experiment on me. All because I had a green SOUL. Seems to be a marker for easy prey.  Actually, he was a monster skeleton like you. But I know how to bide my time. I waited for the right time and got away before he could do anything." You rest your chin on your knees and turn to face your captor. You’re watching Sans as closely as he’s watching you. He suspects he knows who you're talking about

"And what did you think I need?"

" It seems you need a living host or a specimen for an experiment. You got it, so now what?" You eyes drift from Sans to the floor, and your HP lurches down with it.

"You don't get it.  **You** are the experiment. When I said I studied humans, I wasn't lying. I want to find your breaking point. I’ll see how long you can stay there before you snap. Although every individual is different, they’re also very similar once they've given up." Sans’s face tells you he’s said too much, but he tries to play it off by writing in his notebook.

" You know, you could’ve just asked me to do this, and I would have without all that other stuff." You watch Sans write more in his notebook, and you stand up to stretch.

"I doubt you would comply once you saw what I wanted to do. No one ever does.”

" So I am just like everyone else? You’ll never know until you ask. Once I give my word I don't go back on it." You make your way towards the side of the cage closest to Sans, and stare until his eyelights meet you. " I am not a normal human. I enjoy things others don't."

"Everyone has their limits. Morals are always the first to break, after bones of course. Any promise you make is worthless," he scoffs, watching your reaction. You hide your mouth with your hands your shoulders quiver. Are .  . . . . are you laughing? “What’s so funny about your situation?”

" I'm sorry, but did you say morals while talking about doing experiments?" A small smile creeps onto your face. "  _Those_ are the first things to go when it comes to science like this, besides ethics and taboos."

Sans watches you, curious and annoyed. " I was referring to your morals. But I'll admit mine are . . .  . few and far between to say the least."

" My morals?” You chuckle, remembering what you did to the last bastard who shacked you in like this. “I guess you'll just have to find out in time." You keep talking and walk back to the middle of the cage.

"Just know this,Sans: I will trust you if you trust me. If not, this is going to be a very long fight and I won't stop trying to get away from you. I might have a kind soul, but damn if I’m not patient."

He watches you as he calculates the risks and benefits of trying a new test. His curiosity is almost thirsting for new data.  "fine."Sans opens the cage door and waits. You glance tentatively between him and the door." What? Are you trusting me, or just seeing how far I will go?" Sans ignores you and  steps back to his work bench, leaning against it and keeping a close eye on you. You stand up, take your jacket off and roll it into a ball.Then you lay back down in the cage, using your jacket as a pillow. You make a point to lay facing away from the open door.Sans writes something down without looking at his paper before setting it down. He goes around the corner and out of sight.

~A month passes without incident.~

**Notes for the Chapter:**

> Chapter 3 is being typed up as we speak and will be hopefully updated weekly


	3. Chapter 3

**Notes for the Chapter:**

> I couldn't finish this chapter tonight but I will work on it during this week and posting the rest in the next Chapter

~month later~

 

Cold is the first thing that comes to your mind as your laying on the ground. Holding your left arm across your chest as you stare up at the floor above you. Listening to the sound of heavy footsteps moving around very quickly. Trying to ignore the pain in your ribs hoping they aren’t broken but deep down you know for a fact that they are. With every breath you take causing you pain, silently wish you didn’t have to breath. The sound of someone stomping their feet in one place brings your attention back to the sound above.

You haven’t seen Sans since the night he came down and caused you the pain that is now in your ribs. Silently hoping he doesn’t show back up soon.

 

~upstairs~

Sans was sitting at his desk in his room he couldn’t stop staring at his notes. This new subjects data was so different from all the others that he gathered. There had yet to be a time that he regretted adding the illusion of a choice to the experiment. Not like you really had a choice you were there to stay an not leaving unless he said so. But the results were far more than he could have hoped.

The sound of phones alarm going off signaling that it has been over 25 hours since his last visit. Hearing his brother starting to stomp his foot in the kitchen below waiting for him to get out of bed. As he closed his the book that he kept his notes in heading towards the bedroom door. Just in time to hear the front door slam shut as Papyrus left for training with Undyne. He headed down stairs going towards the lab glancing inside the kitchen table seeing the food Papyrus had made. Shaking his head to remind himself to eat it later, he had to check up on the subject for now.

As he walked in seeing you haven’t moved much since he left walking into his small room that holds his tools. Grabbing rolled up blanket tossing it towards you through the open cage door. Didn’t surprise him you didn’t react towards it. He knelt down so he could see her face better.

“Are you awake today?”

He watched you take a few shallow breaths before answering him, “Yes. I am. What will. You require. Today?” Noticing she was stop each time to take a small breath.

“Nothing much today.” Sans was in a good mood as he could be from the shock of his findings. “Just some blood samples and a few questions. Are you still refusing to eat?”

Every part of your body screamed to give an eat some of the food he kept leaving out for you. Some of it was hot and smelled so good like it was inviting you to come over and eat it. But you couldn’t trust it, not after the last time when he drugged you.

“Yes. I am.”

You rolled over towards your right side as you fight the urge to lay back down. As your ribs screamed and knocked out what little air you had in your lungs. After a few tries of getting to your feet.  Catching yourself a couple times to stop and take small quick breaths your finally on your feet. Leaning your back on the bars of the cage looking over at Sans. Noticing it’s easier to take breath now that your standing. Along with Sans not offering you any help.

“Where would you like me. So you can do the blood test?”

Sans walked out of the cage gesturing towards the seat on the other side of the lab. Next to a tray filled with needles, scalpels, and syringes. He made sure to watch as she walks over towards the seat. Reminding himself to monitor if voluntary starvation was an different than food deprivation. You think it was your idea but it wasn’t really.

“I also want to check on your ribs. They seem to be taking longer to heal than normal. Most likely it's the lack of food.”

“ Ribs don’t heal after a day with or without food.” you sits down and soft as you can but your legs give away causing you to flop into the chair harder than you expect to. You watch Sans as she ignores your comment quickly preparing the vials he need.

“ Any hallucination or intrusive thoughts yet?” Reaches for your right arm as he takes the sample of your blood releasing your arm. Looking over at your chest, “Can you lift your shirt or remove it.”


End file.
